<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>值类型</title>
</head>

<body>

</body>
<script>
    // 值类型
    // var a = 100
    // var b = a
    // a = 200
    // console.log(b)  // 100

    // 引用类型
    // var a = { age: 20 }
    // var b = a
    // b.age = 21
    // console.log(a.age) // 21

    // 值类型
    // let a           //undefined
    // let b = 'abc'   //string
    // let c = 100     //number
    // let d = true    //boolean 
    // let e = Symbol('s')
    // console.log(typeof (e))
    // 引用类型
    let f = { x: 100 }  //object
    let g = ['a', '30'] //object
    let h = null        //object
    function fn(){}     //function  特殊引用
    // fn.site = "http"
    console.log(fn)





</script>

</html>